Emission Scenario Development

For the first phase of the Climate Impacts on Regional Air Quality (CIRAQ) study, EPA examined air quality under a future climate scenario with humand-related emissions of ozone and aerosol precursors fixed at 2001 levels, and biogenic emissions from vegetation and soils allowed to vary with simulated meteorology (Nolte et al., 2008). For the second phase of CIRAQ, future air quality is simulated using the same meteorology from phase one and alternative projections of future anthropogenic emissions.

Emission projections for different scenarios of economic growth and technological utilization have been developed by EPA scientists using the MARKet ALlocation (MARKAL) energy system model. MARKAL outputs were converted to source classification code-specific growth factors, which were then used with the Sparse Matrix Operator Kernel Emission (SMOKE) model to generate emissions inputs for use by the EPA's Community Multiscale Air Quality (CMAQ) chemical transport model.

Air quality simulations using these emissions projections and the climatological meteorology described above have been conducted using CMAQ v4.7. Analysis of these simulations is in progress.